Irrigation of crop land at regular intervals during the growing season is an accepted routine in the agricultural industry. To that end many structures and methods have been devised to produce irrigation systems which are reliable, relatively inexpensive when compared to permanent structural installations, ruggedly constructed to provide a long useful life, and which have the capability of irrigating large areas of cropland.
Mobile irrigation systems which comprise a plurality of articulated irrigation pipe sections mounted on ground traversing means which are driven through an arc by motorized means are well known in the art; examples of which may be found by reference to U.S. Pat. Nos. 4,063,569, 4,073,309, 3,979,062 and 3,687,372.
Some of the problems associated with this type of system are; the difficulty in maintaining the individual segments in alignment as the assembly traverses variable terrain, the complicated circuitry and structure necessary to customize the irrigation pattern for a given plot of land, and the failure of the mobile system to cease functioning when an obstruction is present in the arc of rotation of the system.
This last problem has serious potential consequences both for the irrigation system itself and also for the obstructions, which may be trees, a barn, shed, trailer or similar structure.
Most of the systems currently employed have a safety switch incorporated into their design to kill the drive mechanism when the articulated section reach a predetermined degree of misalignment; however, when specific irrigation patterns are desired, it normally entails a complex logic system mechanism, which is costly to install, maintain and repair, and which is not always reliable in operation.